Background: Studies indicate a correlation between obesity and periodontitis. Oxidative stress is involved in the progression of periodontitis. The purpose of this study was to investigate the effects of obesity on gingival oxidative stress in a rat periodontitis model.
Methods: The obese Zucker rats (n = 14) and their lean littermates (n = 14) were each divided into two groups of seven rats. In one of each group, periodontitis was induced by ligature for 4 weeks, whereas the other group was left unligated. The level of 8-hydroxydeoxyguanosine and the ratio of reduced/oxidized glutathione were determined to examine gingival oxidative stress. The serum level of reactive oxygen metabolites and the gingival gene-expression pattern related to oxidative/metabolic stress, inflammation, and cell behavior were also evaluated.
Results: The obese rats weighed more than the lean rats at 4 weeks. Compared to lean rats, obese rats had enhanced gingival 8-hydroxydeoxyguanosine levels and a decreased ratio of reduced/oxidized glutathione in the gingival tissue, with increasing serum reactive oxygen metabolites. However, there were no significant differences in the degree of alveolar bone loss between lean and obese rats, except for teeth with and without ligatures in both rats. In addition, the periodontal lesion in obese rats showed higher 8-hydroxydeoxyguanosine levels and polymorphonuclear leukocyte infiltration than the inflamed ones in lean rats, with downregulation of multiple cytochrome P450 gene expression.
Conclusions: Obesity induced gingival oxidative stress with increasing serum reactive oxygen metabolites in rats. In the periodontal lesion, gene expressions related to a capacity for xenobiotic detoxification were downregulated in the obese model.